Why does zoloft (sertraline) cause vivid dreams?

Side effect: It sounds like a side effect. I would run it by the doctor that prescribed the zoloft (sertraline). Unless it causes sedation, i advise my patients to take their zoloft (sertraline) in the mornings. Also, zoloft (sertraline) is absorbed 50 % better with food, another reason to take it the morning, after breakfast.

Depends: Some medications have in addition to their main effect like blocking serotonin re-uptake like zoloft, (sertraline) they can also affect other neurotransmitter systems responsible for dreams.

Serotonin effect?: I don't believe anyone knows the exact mechanism, but vivid dreams are a well-known side effect of ssri antidepressants (prozac, zoloft, celexa, lexapro, (escitalopram) and paxil). Since the commonality of ssris is that they all increase the net effect of serotonin, this may somehow trigger more vivid dreaming. It's not harmful unless you can't sleep.